Crystalline form of n2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-tr iazine-2,4-diamine

Abstract

The present invention relates to crystalline forms of ethyl[3-[2-chloro-4-fluoro-5-(1-methyl-6- trifluoromethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-3-yl)phenoxy]-2-pyridyloxy]acetate (CAS 353292-31-6), herein after also referred to as "compound of formula (I)". The invention also relates to a process for the production of these crystalline forms, formulations for plant protection and herbicidal compositions which contain one of these crystalline forms

Description

[0001] 241256

[0002] N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4-diamine

[0003] Description

[0004] The present invention relates to crystalline forms of N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4-diamine, herein after also referred to as “compound of formula (I)”.

[0005] The invention also relates to a process for the production of these crystalline forms and to herbicidal composition and plant protection product which contain one of these crystalline forms. Further, the invention relates to method for combating undesired plant growth, wherein one of these crystalline forms is used on plants.

[0006] The compound of formula (I) is the herbicidal active substance of the formula (I):

[0007]

[0008] The compound of formula (I) as such and a general procedure for its production are known from WO 2022 / 161801.

[0009] For the production of active substances on the industrial scale but also for the formulation of active substances, in many cases knowledge concerning the possible existence of crystalline modifications (also described as crystalline forms) or of solvates of the active substance in question, and knowledge of the specific properties of such modifications and solvates and of methods fortheir preparation are of decisive importance. A range of active substances can exist in different crystalline but also in amorphous modifications. Polymorphism is the term used in these cases. A polymorph is a solid, crystalline phase of a compound which is characterized by a specific, uniform packing and arrangement of the molecules in the solid.

[0010] Different modifications of one and the same active substance can sometimes have different properties, for example differences in the following properties: solubility, vapor pressure, dissolution rate, stability against a phase change into a different modification, stability during grinding, suspension stability, optical and mechanical properties, hygroscopicity, crystal form241256

[0011] 2

[0012] and size, filterability, density, melting point, stability to decomposition, color, chemical reactivity or biological activity.

[0013] The applicant’s own attempts to convert the compound of formula (I) into a crystalline solid by crystallization at first resulted in crystal modifications, which could only be handled with difficulty and whose stability is unsatisfactory.

[0014] It has now surprisingly been found that by suitable processes a stable modification of the compounds of formula (I), which does not display the disadvantages of the crystal modifications as described above, is obtained in high purity. The modification is also described below as form III. Further, an additional form II has been identified. In addition, the metastable forms, as mentioned-above has been analyzed and could be described as form la and form lb.

[0015] The form III according to the invention is easier to handle than the previously known form of compound of formula (I), since during production they are obtained in the form of discrete crystals or crystallites. Compared to the known crystalline form la the pure form III, displays increased stability with regard to conversion into another modification. The stability of formulations which contain the compound of formula (I) in form III is also markedly higher than the stability of formulations which contain mixtures of different modifications of the compound of formula (I). Furthermore, the herbicidal compositions and plant protection products, which contain the crystalline form III possesses better herbicidal activity compared to herbicidal compositions and plant protection products using other modifications. Using crystalline form III for formulation, the formulation process of a solid based formulation (e.g. SC or WG) is easier and delivers more reliable and stable formulation products, as re-crystallizations within the formulation products can be avoided.

[0016] The terms “pure form” should be understood to mean that the proportion of the modification in question, based on the total quantity of the compound of formula (I), is at least 90 wt.% and in particular at least 95 wt.%.

[0017] The preferred embodiments of the invention mentioned herein below have to be understood as being preferred either independently from each other or in combination with one another.

[0018] Accordingly, a first object of the present invention relates to the crystalline form III of the compound of formula (I).

[0019] Also, an object is a compound of formula (I) which at least 40 wt.-%, preferably at least 50 wt.-%, more preferably at least 60 wt.-%, even more preferably at least 70 wt.-% consists of the crystalline form III. In one preferred embodiment of the invention, compound of formula (I) consists of in at least 80 wt.-% of the crystalline form III. In one more preferred embodiment of241256

[0020] 3

[0021] the invention, compound of formula (I) consists of in at least 90 wt.-% of the crystalline form III. In one even more preferred embodiment of the invention, compound of formula (I) consists of in at least 95 wt.-% of the crystalline form III. In the most preferred embodiment of the invention, compound of formula (I) consists of in at least 97 wt.-% of the crystalline form III.

[0022] The form III according to the invention can be identified by X-ray powder diffractometry on the basis of its diffraction diagram. Thus, an X-ray powder diffraction diagram recorded using Cu-Ka radiation (1.54178 A) at 25°C shows at least 3, often at least 5, in particular at least 7, and especially all of the reflections quoted in the following table A.1 as °2Q values or as interplanar spacings d:

[0023] Table 111.1

[0024]

[0025] 241256

[0026] 4

[0027]

[0028] Preferably, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 3 of the following reflections, quoted as °29 values: 8.8 ± 0.2, 10.3 ± 0.2, 10.7 ± 0.2, 12.4 ± 0.2, 14.9 ± 0.2, 16.3 ± 0.2, 16.9 ± 0.2, 17.6 ± 0.2, 18.2 ± 0.2, 18.7 ± 0.2, 20.3 ± 0.2, 20.7 ± 0.2, 21.3 ± 0.2, 22.3 ± 0.2, 22.9 ± 0.2, 24.8 ± 0.2, 27.6 ± 0.2, 28.1 ± 0.2, 28.8 ± 0.2, 30.0 ± 0.2 and 31.2 ± 0.2°.

[0029] More preferably, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 5 of the following reflections, quoted as °29 values: 8.8 ± 0.2, 10.3 ± 0.2, 10.7 ± 0.2, 12.4 ± 0.2, 14.9 ± 0.2, 16.3 ± 0.2, 16.9 ± 0.2, 17.6 ± 0.2, 18.2 ± 0.2, 18.7 ± 0.2, 20.3 ± 0.2, 20.7 ± 0.2, 21.3 ± 0.2, 22.3 ± 0.2, 22.9 ± 0.2, 24.8 ± 0.2, 27.6 ± 0.2, 28.1 ± 0.2, 28.8 ± 0.2, 30.0 ± 0.2 and 31.2 ± 0.2°.

[0030] In particular, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 7 of the following reflections, quoted as °29 values: 8.8 ± 0.2, 10.3 ± 0.2, 10.7 ± 0.2, 12.4 ± 0.2, 14.9 ± 0.2, 16.3 ± 0.2, 16.9 ± 0.2, 17.6 ± 0.2, 18.2 ± 0.2, 18.7 ± 0.2, 20.3 ± 0.2, 20.7 ± 0.2, 21.3 ± 0.2, 22.3 ± 0.2, 22.9 ± 0.2, 24.8 ± 0.2, 27.6 ± 0.2, 28.1 ± 0.2, 28.8 ± 0.2, 30.0 ± 0.2 and 31.2 ± 0.2°.

[0031] The crystal structure of form III was determined via single crystal X-ray diffraction at 100 K. The structure was also refined from powder X-ray diffraction data at room temperature.241256

[0032] 5

[0033] Studies on single crystals of form III demonstrate that the underlying crystal structure is monoclinic. The unit cell has the space group P2i / c. The characteristic data of the crystal structure of form III (determined at 100 K) are compiled in the following table 111.2

[0034] Table III.2 Crystallographic characteristics of form III

[0035]

[0036] a,b,c = unit cell length

[0037] a,p,y = unit cell angle

[0038] Z = number of molecules in the unit cell

[0039] Form III displays a thermogram with a characteristic melting peak in the range from 210 to 225°C. The melting point, determined as the onset of the melting peak, typically lies at 216-218 °C The values quoted here relate to values determined by differential calorimetry (differential scanning calorimetry, DSC).

[0040] The production of the form III of the compound of formula (I) according to the invention is effected by crystallization from a solution of the compound of formula (I).

[0041] The solution of compound of formula (I) can for example be prepared by the following methods:241256

[0042] 6

[0043] (1) Dissolution of the compound of formula (I), in one of the solvents mentioned below, or (2) Preparation of the compound of formula (I) by a chemical reaction and transfer of the reaction mixture, if necessary after removal of reagents and / or side products, into an organic solvent and I or water and I or mixtures thereof suitable according to the invention.

[0044] For the preparation of the solution by dissolution of the compound of formula (I), essentially any known form of compound of formula (I) can be used. Often amorphous compound of formula (I) or a mixture of different crystalline modifications or a mixture of amorphous and crystalline compound of formula (I) will be used. Also suitable are crystalline forms of compound of formula (I) and mixtures thereof, for example the form la or lb according to the invention and also any mixtures of these forms.

[0045] The dissolution of the compound of formula (I) is usually effected at temperatures in the range from 20 to 100°C. In one embodiment of the invention, the dissolution of the compound of formula (I) is effected at elevated temperature, in particular at 60°C, and naturally the temperature used for dissolution will not exceed the boiling point of the solvent. The dissolution is often effected at temperatures in the range from 20°C to 80°C.

[0046] The solution of the compound of formula (I) can also be prepared by transferring a reaction mixture obtained by a chemical reaction, which contains the compound of formula (I), if necessary after removal of reagents and / or side products, into an organic solvent and I or water and I or mixtures thereof suitable according to the invention. This can be effected in such a manner that the reaction is performed in an organic solvent or solvent mixture which consists at least partly, preferably at least 50 wt.-%, of a solvent suitable for the crystallization and, if necessary a workup is performed during which excess reagents and any catalysts present and any unsuitable solvents present are removed. The preparation of a solution of the compound of formula (I) by chemical reaction of a suitable precursor of compound of formula (I) can be effected by analogy to the methods which are described in the state of the art cited at the beginning, to which full reference is hereby made.

[0047] The production of the form III of the compound of formula (I) according to the invention is effected by crystallization from a solution of the compound of formula (I) in a suitable organic solvent.

[0048] Suitable solvents for the crystallization of form III are esters such as ethyl acetate, n-butyl acetate; nitriles such as acetonitrile; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; alcohols such as methanol, ethanol, isopropanol; dipolar aprotic solvents such as N,N-dimethylformamide (DMF); water and mixtures of the afore-mentioned solvents.

[0049] Preferred solvents are alkyl alcohols such as methanol, ethanol, isopropanol most preferred is ethanol.241256

[0050] 7

[0051] In order to obtain form III of the compound of formula (I), the crystallization is preferably effected at most 90°C, in particular from 70 °C to -20 °C in a cooling crystallization step.

[0052] Crystallization of form III is preferably effected under controlled conditions, i.e. the conditions of the crystallization are chosen to achieve a slow crystallization rate.

[0053] For this, in a first step i) a solution of the compound of formula (I) in one of the aforesaid organic solvents is prepared, and then in a second step ii) crystallization of the compound of formula (I) is effected.

[0054] The concentration of compound of formula (I) in the solution used for the crystallization naturally depends on the nature of the solvent and the solution temperature and often lies in the range from 5 to 1000 g / l. Suitable conditions can be determined by the person skilled in the art by routine experiments.

[0055] The crystallization is as a rule carried out until at least 80 wt.-%, preferably at least 90 wt.-%, of the compound of formula (I) used crystallizes out.

[0056] If the crystallization of form III is effected by cooling, the cooling rate is preferably equal or less than 20 K / h.

[0057] The crystallization of form III can be promoted or accelerated by seeding with seed crystals of form III, for example by adding seed crystals of form III before or during the crystallization.

[0058] If seed crystals are added during the crystallization, the quantity thereof is typically 0.001 to 10 wt.-%, often 0.005 to 5 wt.-%, in particular 0.01 to 1 wt.-% and especially 0.05 to 0.5 wt.-%, based on the dissolved compound of formula (I).

[0059] If the crystallization is performed in the presence of seed crystals of form III, these are preferably only added at a temperature at which the saturation concentration of the compound of formula (I) in the solvent in question has been reached, i.e. at or below that temperature at which the dissolved quantity of compound of formula (I) forms a saturated solution in the solvent in question. The person skilled in the art can determine the temperature dependence of the saturation concentration in a solvent in routine experiments.

[0060] Alternatively, the crystallization can also be effected by addition of a "non-solvent" (i.e. a solubility decreasing solvent) e.g. by addition of a nonpolar solvent or by addition of water, forexample from 5 to 60 vol.%, in particular 20 to 55 vol.% and especially from 30 to 50 vol.%, based on the volume of the organic solvent or solvent mixture used for dissolution of the compound of formula (I). The addition of the nonpolar solvent or the addition of water are preferably effected over a prolonged period, for example over a period from 10 mins to 5 hrs, in particular over a period from 20 mins to 2.5 hrs. If the crystallization of form III is effected by the addition of a "non-solvent", the addition of the non-solvent is preferably at a slow rate, e.g. less than 10 % v / v per minute, based on the volume of the compound of formula (I) solution. Often the addition will be done in such a manner that the nonpolar solvent or water is added until the discernable onset of the crystallization and the mixture thus obtained is then left for a time, during which the crystallization of the form III proceeds. If necessary, the mixture can then be cooled for completion of the crystallization.

[0061] In particular, the addition of the nonpolar solvent or the addition of water and the addition of seed crystals can be combined.

[0062] The addition of the nonpolar solvent can be effected in the form of a pure nonpolar solvent or in the form of a mixture of a nonpolar solvent with a solvent used for the dissolution. Examples of nonpolar solvents are aliphatic and cycloaliphatic hydrocarbons with preferably 5 to 10 C atoms such as pentane, hexane, cyclopentane, cyclohexane, isohexane, cycloheptane, octane, decane or mixtures thereof.

[0063] The isolation of the form III from the crystallization product, i.e. the separation of the form III from the mother liquor, is effected by usual techniques for the separation of solid components from liquids, for example by filtration, centrifugation or by decantation. As a rule, the isolated solid will be washed, for example with the solvent used for the crystallization, with water or with a mixture of the organic solvent used for the crystallization with water. The washing can be effected in one or more steps, washing with water often being used in the last washing step. The washing is typically effected at temperatures below 30°C, often below 25°C and in particular below 20°C, in order to keep the loss of valuable product as small as possible. Next, the form III obtained can be dried and then supplied for further processing. Often, however, the moist active substance obtained after washing, in particular an active substance moist with water, will be supplied directly for the further processing.

[0064] By means of the crystallization according to the invention, the form III is obtained with a compound of formula (I) content of as a rule at least 90 wt.-%, often 94 wt.-%, in particular at least 96 wt.-%.

[0065] The content of form III, based on the total quantity of compound of formula (I), is typically at least 90% and often at least 95 % or at least 96%.9

[0066] The preparation of the compound of formula (I) as such used for the production of the form III can be effected by the process described in WO 2022 / 161801 , to which full reference is hereby made.

[0067] A further object of the present invention relates to the crystalline form II of compound of formula (I). Also an object is a compound of formula (I) which at least 90 wt.-%, in particular at least wt.-95 % consists of the crystalline form II. Form II is a DMSO solvate of compound of formula (I).

[0068] Table 11.1

[0069]

[0070]

[0071] A further object of the present invention relates to the crystalline form la and lb of compound of formula (I). Also an object is a compound of formula (I) which at least 90 wt.-%, in particular at least wt.- 95 % consists of the crystalline form la or lb. Forms la and lb are the metastable forms of compound of formula (I).

[0072] The form la according to the invention can be identified by X-ray powder diffractometry on the basis of its diffraction diagram. Thus, an X-ray powder diffraction diagram recorded using Cu-Ka radiation (1.54178 A) at 25°C shows at least 3, preferably at least 5, in particular at least 7, and especially all of the reflections quoted in the following table 1.1a as 29 values or as interplanar spacings d:

[0073] Table la.1

[0074]

[0075] 241256

[0076] 11

[0077]

[0078] Preferably, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 3 of the following reflections, quoted as °29 values: 7.4 ± 0.2, 9.1 ± 0.2, 10.5 ± 0.2, 14.8 ± 0.2, 15.6 ± 0.2, 17.2 ± 0.2, 19.2 ± 0.2, 22.3 ± 0.2, 23.0 ± 0.2, 24.3 ± 0.2, 27.1 ± 0.2, 29.1 ± 0.2, 30.0 ± 0.2, 36.2 ± 0.2.

[0079] More preferably, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 5 of the following reflections, quoted as °29 values: 7.4 ± 0.2, 9.1 ± 0.2, 10.5 ± 0.2, 14.8 ± 0.2, 15.6 ± 0.2, 17.2 ± 0.2, 19.2 ± 0.2, 22.3 ± 0.2, 23.0 ± 0.2, 24.3 ± 0.2, 27.1 ± 0.2, 29.1 ± 0.2, 30.0 ± 0.2, 36.2 ± 0.2.

[0080] In particular, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 7 of the following reflections, quoted as °29 values: 7.4 ± 0.2, 9.1 ± 0.2, 10.5 ± 0.2, 14.8 ± 0.2, 15.6 ± 0.2, 17.2 ± 0.2, 19.2 ± 0.2, 22.3 ± 0.2, 23.0 ± 0.2, 24.3 ± 0.2, 27.1 ± 0.2, 29.1 ± 0.2, 30.0 ± 0.2, 36.2 ± 0.2.

[0081] Form la displays a thermogram showing a degradation starting slowly above 170°C. DSC data shows an endothermal event at around 100-140°C, followed by the melting point of form III with an onset of 218°C and 218°C peak maximum. The conversion of form I into form III was shown by storing form la for 5 min at 130°C obtaining a sample of form III.

[0082] During storage at room temperature for the time of about few days form la (dry powder) converts partially into form III.

[0083] The form lb according to the invention can be identified by X-ray powder diffractometry on the basis of its diffraction diagram. Thus, an X-ray powder diffraction diagram recorded using Cu-Ka radiation (1.54178 A) at 25°C shows at least 3, preferably at least 5, in particular at least 7, and especially all of the reflections quoted in the following table 1.1b as 29 values or as interplanar spacings d:

[0084] Table 1.1b

[0085]

[0086] 12

[0087]

[0088] Preferably, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 3 of the following reflections, quoted as °29 values: 7.3 ± 0.2, 9.0 ± 0.2, 10.5 ± 0.2, 14.7 ± 0.2, 15.8 ± 0.2, 16.1 ± 0.2, 19.4 ± 0.2, 20.0 ± 0.2, 22.7 ± 0.2, 23.5 ± 0.2, 24.4 ± 0.2, 25.0 ± 0.2, 27.3 ± 0.2, 28.3 ± 0.2, 29.3 ± 0.2, 29.8 ± 0.2, 30.8 ± 0.2, 31 .7 ± 0.2 and 35.2 ± 0.2.13

[0089] More preferably, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 5 of the following reflections, quoted as °29 values: 7.3 ± 0.2, 9.0 ± 0.2, 10.5 ± 0.2, 14.7 ± 0.2, 15.8 ± 0.2, 16.1 ± 0.2, 19.4 ± 0.2, 20.0 ± 0.2, 22.7 ± 0.2, 23.5 ± 0.2, 24.4 ± 0.2, 25.0 ± 0.2, 27.3 ± 0.2, 28.3 ± 0.2, 29.3 ± 0.2, 29.8 ± 0.2, 30.8 ± 0.2, 31.7 ± 0.2 and 35.2 ± 0.2.

[0090] In particular, an: X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 7 of the following reflections, quoted as °29 values: 7.3 ± 0.2, 9.0 ± 0.2, 10.5 ± 0.2, 14.7 ± 0.2, 15.8 ± 0.2, 16.1 ± 0.2, 19.4 ± 0.2, 20.0 ± 0.2, 22.7 ± 0.2, 23.5 ± 0.2, 24.4 ± 0.2, 25.0 ± 0.2, 27.3 ± 0.2, 28.3 ± 0.2, 29.3 ± 0.2, 29.8 ± 0.2, 30.8 ± 0.2, 31.7 ± 0.2 and 35.2 ± 0.2.

[0091] The following illustrations and examples serve to illustrate the invention and should not be regarded as limiting.

[0092] Figure 1 shows an X-ray powder diffraction diagram of form III. The X-ray diffraction diagram of form III was recorded using Cu-Ka radiation (1.54178 A) at 25°C.

[0093] Figure 2 shows an X-ray powder diffraction diagram of form II. The X-ray diffraction diagram was recorded under the conditions stated for Figure 1.

[0094] Figure 3 shows an X-ray powder diffraction diagram of form la. The X-ray diffraction diagram was recorded under the conditions stated for Figure 1.

[0095] Figure 4 shows an X-ray powder diffraction diagram of form lb. The X-ray diffraction diagram was recorded under the conditions stated for Figure 1.

[0096] Melting points:

[0097] The melting points were determined using DSC with a Mettler Toledo DSC 823e / 700 / 229 module. The samples were placed in aluminum standard pans. The sample size in each case was 1 to 10 mg. The heating rate was 10°C / min. The samples were purged with a stream of nitrogen during the experiment. The melting point was determined as the extrapolated peak onset temperature (also called onset temperature) defined by the point of intersection of the tangent at the half height of the melting peak, on the principal side of the peak with the linearly extrapolated initial base line.

[0098] Powder X-Ray Diffraction (PXRD)

[0099] Laboratory PXRD patterns were recorded with a PANalytical X'Pert Pro or Rigaku MiniFlex600 X-ray diffractometer using Cu Ka radiation in reflection geometry (Bragg-Brentano).241256

[0100] 14

[0101] PANalytical X'Pert Pro: The sample is placed in a silicon single crystal sample holder of 0.2 mm depth and gently and precisely flattened. The tube voltage is 45 kV and current is 40 mA. The PXRD data are collected at room temperature in the range from 29 =3.0°-40.0° with increments of 0.017° and measurement time of 20 to 200 s / step.

[0102] Rigaku MiniFlex600: The sample is placed in a glas sample holder of 0.2 mm depth and gently and precisely flattened. The tube voltage is 40 kV and current is 15 mA. The PXRD data are collected at room temperature in the range from 29 =3.0°-40.0°.

[0103] Single crystal X-ray diffraction:

[0104] Data were collected on a Bruker D8 venture diffractometer with a PHOTON-II CCD detector in (p and co scans using graphite-monochromated Cu-Ka radiation (A = 1.54178 A).

[0105] The structure was solved and refined using the Bruker SHELXTL Software Package.

[0106] Example 1: Preparation of form III of compound of formula (I) by crystallization from chlorobenzene / methanol / water

[0107] 15 g (0.053 mol) 1-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-3-carbamimidoyl-guanidine (97.5 %) were charged together with 116.5 g chlorobenzene and 14.9 g (0.122 mol) methyl 2-fluoroisobutyrate (98 %) to a 250 ml reactor and heated to 25 °C. 21.9 g (0.122 mol) of sodium methylate solution (30 % in methanol) were added over 30 min at 55-27 °C under agitation. After poststirring over night at room temperature, 29.1 g demineralized water were added at 25-26 °C over 30 min. After 30 min poststirring, the suspension was cooled down to 0°C over 2.5 h. The precipitated solid was isolated by suction filtration and washed twice with 20 g water each. Drying was performed in a drying cabinet (120 °C, 30 mbar). 17.2 g 1,3,5-triazine-2,4-diamine, A / 2-(3-chloro-5,6-difluoro-2-methoxyphenyl)-6-(1 -fluoro- 1 -methylethyl) with a purity of 100 % (quantitative HPLC) were obtained, corresponding to a yield of 93.4 %.

[0108] Example 2: Preparation of form II of compound of formula (I) by crystallization from form III

[0109] 5 g Form III dissolved in 15 g DMSO in a 100 ml round-bottomed flask at room temperature. Vacuum of 0.5-1 mbar applied at 23 °C and solvent completely evaporated without heating or cooling. Drying of obtained solid at 23 °C over 5 h at 0.4 mbar.

[0110] Example 3: Preparation of form la of compound of formula (I) according to WO 2022 / 161801

[0111] 5-Chloro-2,3-difluoro-6-methoxy-aniline (10.7 g, 55.27mmol) and 4-chloro-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazin-2-amine (10.54 g, 55.27mmol) were dissolved in 100 mL dioxane. After the addition of 3 equivalents of 4M HCI in dioxane, the reaction mixture was stirred at 90°C for4h. Extractive work-up H2O / EtOAc and the crude was purified via column chromatography241256

[0112] 15

[0113] (Teledyne ISCO Rf+, Macherey Nagel chromabond flash RS40 C18, 100% H2O to 100% MeOH) and freeze-dried resulting in the formation of form la.

[0114] Example 4: Preparation of form lb of compound of formula (I) according to WO 2022 / 161801

[0115] 0.5 g of compound of formula (I), form III, were dissolved in 15 g ethyl acetate under heating in a 100 ml round-bottomed flask and afterwards cooled down in a dry ice I acetone bath. Vacuum of 0.5-1 mbar applied at < - 60 °C. Cooling discontinued for slow warming up during solvent evaporation and solid crystallization.

[0116] Example 5: Stability of form la vs. form III

[0117] 100 mg form III was suspended in 3 ml EtOH. The suspension was stirred and 50 mg form la was added. The suspension was stirred for one day. The solid material was investigated by PXRD to show that all material was form III.

[0118] Thus, the above described experiment shows, that at room temperature form III is more stable than form la.

[0119] Example 6;

[0120] Comparison of the biological activity of the crystalline form I and III

[0121] Both crystalline forms (I, III) were applied in a greenhouse trial. The crystallin forms I and III were formulated as WP with Al content of 50 g / kg (5%). Shortly before application they were given into water according to target dose rate and the water volume of application was 375 L / ha.

[0122] Weeds were at preemergence timing (PRE) or postemergence timing (POST) (BBCH 13 to 14). Given data is from 20 days after application / treatment.

[0123] Application rate in (g Al / ha)

[0124]

[0125] 241256

[0126] 16

[0127]

Claims

24125617Claims:

1. N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4- diamine, consisting of at least 40 wt.-% of the crystalline form III, which in an X-ray powder diffraction diagram at 25°C and Cu-Ka radiation displays at least 3 of the following reflections, quoted as °29 values: 8.8 ± 0.2, 10.3 ± 0.2, 10.7 ± 0.2, 12.4 ± 0.2, 14.9 ± 0.2, 16.3 ± 0.2, 16.9 ± 0.2, 17.6 ± 0.2, 18.2 ± 0.2, 18.7 ± 0.2, 20.3 ± 0.2, 20.7 ± 0.2, 21.3 ± 0.2, 22.3 ± 0.2, 22.9 ± 0.2, 24.8 ± 0.2, 27.6 ± 0.2, 28.1 ± 0.2, 28.8 ± 0.2, 30.0 ± 0.2 and 31.2 ± 0.2°.

2. N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4- diamine according to claim 1, wherein the form III displays at least 5 of the following reflections, quoted as °29 values: 8.8 ± 0.2, 10.3 ± 0.2, 10.7 ± 0.2, 12.4 ± 0.2, 14.9 ± 0.2, 16.3 ± 0.2, 16.9 ± 0.2, 17.6 ± 0.2, 18.2 ± 0.2, 18.7 ± 0.2, 20.3 ± 0.2, 20.7 ± 0.2, 21.3 ± 0.2, 22.3 ± 0.2, 22.9 ± 0.2, 24.8 ± 0.2, 27.6 ± 0.2, 28.1 ± 0.2, 28.8 ± 0.2, 30.0 ± 0.2 and 31.2 ± 0.2°.

3. N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4- diamine according to claim 1 or 2, wherein the form III displays at least 7 of the following reflections, quoted as °29 values: 8.8 ± 0.2, 10.3 ± 0.2, 10.7 ± 0.2, 12.4 ± 0.2, 14.9 ± 0.2, 16.3 ± 0.2, 16.9 ± 0.2, 17.6 ± 0.2, 18.2 ± 0.2, 18.7 ± 0.2, 20.3 ± 0.2, 20.7 ± 0.2, 21.3 ± 0.2, 22.3 ± 0.2, 22.9 ± 0.2, 24.8 ± 0.2, 27.6 ± 0.2, 28.1 ± 0.2, 28.8 ± 0.2, 30.0 ± 0.2 and 31.2 ± 0.2°.

4. N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4- diamine as claimed in any of claims 1 to 3 consisting of at least 60 wt.-% of crystalline form III.

5. N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4- diamine as claimed in any of claims 1 to 4 consisting of at least 90 wt.-% of crystalline form III.

6. N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4- diamine as claimed in any of claims 1 to 5 consisting of at least 97 wt.-% of crystalline form III.

7. A process to produce the crystalline form III as claimed in any of claims 1 to 6, comprising:i) preparation of a solution of N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro- 1-methyl-ethyl)-1,3,5-triazine-2,4-diamine,24125618ii) effecting a crystallization of N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1-fluoro- 1-methyl-ethyl)-1,3,5-triazine-2,4-diamine.

8. A herbicidal composition comprising a herbicidal active amount of N2-(5-chloro-2,3- difluoro-6-methoxy-phenyl)-6-(1-fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4-diamine as claimed in any of claims 1 to 6, and at least one further active compound selected from herbicides of class b1) to b15):b1) lipid biosynthesis inhibitors;b2) acetolactate synthase inhibitors;b3) photosynthesis inhibitors;b4) protoporphyrinogen-IX oxidase inhibitors,b5) bleacher herbicides;b6) enolpyruvyl shikimate 3-phosphate synthase inhibitors;b7) glutamine synthetase inhibitors;b8) 7,8-dihydropteroate synthase inhibitors;b9) mitosis inhibitors;b10) inhibitors of the synthesis of very long chain fatty acids;b11) cellulose biosynthesis inhibitors;b12) decoupler herbicides;b13) auxinic herbicides;b14) auxin transport inhibitors andb15) other herbicides selected from the group consisting of bromobutide, chlorflurenol, chlorflurenol-methyl, cinmethylin, cumyluron, dalapon, dazomet, difenzoquat, difenzoquat-metilsulfate, dimethipin, DSMA, dymron, endothal and its salts, etobenzanid, flamprop, flamprop-isopropyl, flamprop-methyl, flamprop-M-isopropyl, flamprop-M- methyl, flurenol, flurenol-butyl, flurprimidol, fosamine, fosamine-ammonium, indanofan, indaziflam, maleic hydrazide, mefluidide, metam, methiozolin, methyl azide, methyl bromide, methyl-dymron, methyl iodide, MSMA, oleic acid, oxaziclomefone, pelargonic acid, pyributicarb, quinoclamine, tetflupyrolimet, triaziflam, tridiphane and 6-chloro-3-(2- cyclopropyl-6-methylphenoxy)-4-pyridazinol and its salts and esters including their agriculturally acceptable salts or derivatives.

9. A plant protection agent containing N2-(5-chloro-2,3-difluoro-6-methoxy-phenyl)-6-(1- fluoro-1-methyl-ethyl)-1,3,5-triazine-2,4-diamine as claimed in any of claims 1 to 6, and one or more additives customary for the formulation of plant protection agents.2412561910. The plant protection agent as claimed in claim 9 in the form of an aqueous suspension concentrate.

11. The plant protection agent as claimed in claim 9 in the form of a non-aqueous suspension concentrate.

12. The plant protection agent as claimed in claim 9 in the form of a powder or granules dispersible in water.

13. A method for combating undesired plant growth, wherein N2-(5-chloro-2,3-difluoro-6- methoxy-phenyl)-6-(1 -fluoro- 1-methyl-ethyl)-1, 3, 5-triazine-2,4-diamine as claimed in any of claims 1 to 6 is used on plants, the habitat thereof and / or on seeds.

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